Axle housing assembly and method

ABSTRACT

An apparatus that includes a first member, an insert, and an object. The first member made of a first metal and has a first exterior surface and a first end. A pocket is formed in the exterior surface of the first end. The insert is made of a second, different metal. The insert is connected to the pocket and has a second exterior surface that is flush with the first exterior surface. The object is formed of the second metal and is resistance welded to the insert. The second metal is steel and the first metal is a metal that cannot be resistance welded directly to steel.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a continuation of U.S. patent application Ser. No.12/150,011, which is a continuation U.S. patent application Ser. No.11/032,348 filed on Jan. 10, 2005. The disclosures of each of the aboveapplications are incorporated by reference in their entirety.

FIELD OF THE INVENTION

The present invention relates to an axle housing assembly and moreparticularly relates to a device and a method for coupling a cast irontube assembly to a cast iron carrier assembly.

BACKGROUND OF THE INVENTION

An axle housing assembly can include the carrier assembly and two tubeassemblies that can be press-fit into the carrier assembly. The carrierassembly can hold a differential gear set and each of the tubeassemblies can hold an axle shaft that can connect the differential gearset to each of a pair of wheels. Traditionally, the carrier assembly ismade of cast iron and the tube assemblies are made of steel. Multiplecomponents made from steel can be formed from or welded to each of thesteel tube assemblies, for example steering knuckles, suspensionbrackets and/or hydraulic connectors.

In addition to coupling each of the tube assemblies to the carrierassembly with the press-fit, each of the tube assemblies can beslug-welded to the carrier assembly. Slug-welding, for example, caninclude forming a plurality of holes at two locations where each of thetube assemblies couples to the carrier assembly. Steel plugs can beinserted into the plurality of holes and contact each of the steel tubeassemblies. The steel plugs can then be welded to each of the tubeassemblies to further secure each of the tube assemblies to the castiron carrier assembly.

In another example, each of the tube assemblies can be made from castiron. Forming the tube assemblies from cast iron can reduce complexityand therefore save cost, but renders the connection of steel plugs tothe tube assemblies somewhat more complex.

SUMMARY OF THE INVENTION

The present invention includes an axle housing assembly including a castiron tube having a pocket. The pocket is formed proximate a first end ofthe cast iron tube. The pocket is also disposed generally transverse toa longitudinal axis of the cast iron tube. The axle housing assemblyalso includes an insert made of steel connected to the pocket.

In still another form, the present disclosure provides an apparatus thatincludes a first member, an insert, and an object. The first member madeof a first metal and has a first exterior surface and a first end. Apocket is formed in the exterior surface of the first end. The insert ismade of a second, different metal. The insert is connected to the pocketand has a second exterior surface that is flush with the first exteriorsurface. The object is formed of the second metal and is resistancewelded to the insert. The second metal is steel and the first metal is ametal that cannot be resistance welded directly to steel.

Further areas of applicability of the present invention will becomeapparent from the detailed description provided hereinafter. It will beunderstood that the detailed description and specific examples, whileindicating the various embodiments of the invention, are intended forpurposes of illustration only and are not intended to limit the scope ofthe invention.

BRIEF DESCRIPTION OF THE DRAWINGS

The present invention will become more fully understood from thedetailed description, the appended claims and the accompanying drawings,wherein:

FIG. 1 is a top view of an exemplary vehicle showing an axle assemblyhousing constructed in accordance with the various embodiments of thepresent invention;

FIG. 2 is a perspective view of a carrier assembly and a tube assemblyconstructed in accordance with the various embodiments of the presentinvention;

FIGS. 3A-3F are cross-sectional views showing various embodiments of asteel insert positioned in the tube assembly constructed in accordancewith the various embodiments of the present invention;

FIG. 4 is a perspective view of the tube assembly showing an annularmember made of steel disposed in an annular depression formed on thetube assembly constructed in accordance with the various embodiments ofthe present invention;

FIG. 5 is a cross-sectional view of FIG. 4 showing positions of theannular member with respect to a first end of the tube assembly; and

FIG. 6 is similar to FIG. 2 and shows the tube assembly coupled to thecarrier assembly.

DETAILED DESCRIPTION OF THE VARIOUS EMBODIMENTS

The following description of the various embodiments is merely exemplaryin nature and is in no way intended to limit the invention, itsapplication or uses.

With reference to FIG. 1, an exemplary vehicle 10 is shown with an axleassembly 12 constructed in accordance with the teachings of the presentinvention. The exemplary vehicle 10 can include an engine 14, a frame16, a transmission 18, a driveshaft 20, a pair of driven wheels 22 and apair of optionally-driven wheels 24. The engine 14 produces an outputhaving a torque component in a manner known in the art and transmits theoutput to the transmission 18. The transmission 18 can reduce the speedand increase the torque of the output produced by the engine 14 andtransmit a torque to the axle assembly 12 through the driveshaft 20. Theaxle assembly 12 can transmit the torque to the pair of driven wheels 22to propel the vehicle 10. It will be appreciated that theoptionally-driven wheels 24 can connect to the transmission 18 in amanner known in the art (e.g., a four-wheel drive configuration).

With reference to FIGS. 2 and 6, the axle assembly 12 can include acarrier assembly 26 and two tube assemblies 28. The carrier assembly 26can include a carrier housing 30 and a carrier housing cover 32 that isremovably connected to the carrier housing 30 with a plurality offasteners 34. The carrier housing 30 can define a carrier cavity 36 inwhich a differential gear set 38 can reside. The carrier housing 30 canbe configured to include one or more suspension brackets 40, a pair oftube assembly apertures 42 and/or a pinion aperture 44. The suspensionbrackets 40 can connect to an exemplary suspension system in a mannerthat is well known in the art. The carrier housing 30 can be made ofcast iron.

Each of the tube assemblies 28 can include a tube member 46 having afirst end 48 that can be configured to connect with the carrier assembly26 and a second end 50 that can connect with either one of the drivenwheels 22 (FIG. 1). The tube assemblies 28 can include suspensionbrackets 52, steering knuckles 54, and/or a coil spring holder 56 ifappropriate. An axle shaft 58 can be disposed in each tube member 46 andcan be coupled for rotation with the differential gear set 38 and to oneof the driven wheels 22 (FIG. 1) in a manner known in the art. Each ofthe axle shafts 58 can be journally supported for rotation by one ormore axle shaft bearings (not shown) that can be housed in the tubemember 46. The differential gear set 38 can be configured to transferpower received from the driveshaft 20 to the axle shafts 58.

Each of the tube assemblies 28 and the carrier housing 30 can besubstantially made from cast iron and can be made from respectivecastings. It will be appreciated that the suspension brackets 40, 52,the coil spring holder 56, the pair of tube assembly apertures 42, thepinion aperture 44 and/or the steering knuckles 54 can be formed duringthe casting process. One exemplary type of casting process is commonlyreferred to as Lost Foam casting. The Lost Foam casting process andother exemplary suitable casting processes are disclosed in greaterdetail in commonly assigned U.S. Pat. No. 6,189,413 B1, entitled CaptiveMolding With Dissimilar Material Inserts, issued Feb. 20, 2001, which ishereby incorporated by reference as if fully set forth herein.

Each of the tube assembly apertures 42 on the carrier housing 30 caninclude a collar 60 that can be configured so that the tube assembly 28can be press-fit therein. The collar 60 can include an outer annularsurface 62 in which a plurality of holes 64 can be formed therethrough.The collar 60 can have a dimension that defines a thickness 66. Aplurality of pins or plugs 68, which can be formed of steel, can beinserted into the respective holes 64 formed in the collar 60 and intocontact with the tube assembly 28. It will be appreciated that theplurality of holes 64 can be formed in the collar 60 by various suitableforming processes, for example, machining the holes 64 into the collar60 or forming the holes 64 in the collar 60 during an exemplary castingprocess. It will also be appreciated that the plugs 68 can be cast inplace when the cast iron carrier housing 30 is formed in accordance withthe methodology described in the above-referenced U.S. Pat. No.6,189,413 B1.

With reference to FIGS. 2 and 3A-3F, the first end 48 of the tubeassembly 28 can include one or more pockets 70. An insert 72 that can bemade of steel can be disposed in the pocket 70. The pocket 70 can beformed in the first end 48 with various suitable methods, such asmachining the pocket 70 in the first end 48. It will be appreciated thatthe pocket 70 can be formed during the casting process with the insert72 disposed in and secured to the pocket 70. In the Lost Foam castingprocess, for example, the insert 72 can be placed in a foam mold (notshown) used in the Lost Foam process such that when molten iron ispoured into the foam mold the finished casting will include the insert72 fixedly attached to the pocket 70.

With reference to FIG. 3A, one embodiment of the present inventionincludes a bottom 74 of the pocket 70 that can have a curvature 76,which approximates a curvature of the tube assembly 28. A pair of walls80 of the pocket 70 can be about parallel to each other. The pair ofwalls 80 of the pocket 70 can be formed such that the walls 80 wouldcompletely or partially converge, as indicated by reference number 82and shown in FIG. 3E, or diverge as indicated by reference number 84 andshown in phantom in FIG. 3A. It will be appreciated that a pair of sides86 and a bottom 88 of the insert 72 can have a shape that iscomplimentary to the pocket 70. It will also be appreciated that theinsert 72 and the pocket 70 need not be rectangular in shape but may becircular, oval or other suitable shapes. As such, a circular insert 72 areceived in a circular pocket 70 a is shown in FIG. 2. Moreover, thevarious below described configurations of the pair of sides 86 of theinsert 72 and the pair of walls 80 of the pocket 70 may be applicable tothe circular insert 72 a and the circular pocket 70 a.

With reference to FIG. 3B, one embodiment of the present invention caninclude the insert 72 that can have serrated or dovetail walls 80. Thepocket 70 can have walls with a complementary shape, generally indicatedby reference number 90, to further secure the insert 72 into the pocket70. With reference to FIG. 3C, one embodiment of the present inventioncan include a mechanical fastener 92 that can be used to secure theinsert 72 into the pocket 70. By way of example, the fastener 92 can bethreaded through the insert 72 and the pocket 70 formed into the tubeassembly 28. With reference to FIG. 3D, one embodiment of the presentinvention can include the insert 72 that can include a post 94 extendingfrom the insert 72 into the pocket 70 formed in the tube assembly 28.The post 94 can extend in a direction toward a center 96 (FIG. 4) of thetube assembly 28. By way of example, an aperture 98 can be formed in thepocket 70 and be configured to accept the post 94, for example, with ataper-lock or an interference fit.

With reference to FIG. 3F, one embodiment of the present invention caninclude the insert 72 that can be placed in the pocket 70 and securedwith a suitable adhesive 100. The adhesive 100 placed between the insert72 and the pocket 70 can include various suitable acrylics or epoxies.Suitable adhesives for use in accordance with the present invention mayinclude, for example, an acrylic adhesive comprising a urethanemethacrylate. By way of example, one suitable acrylic adhesive isLoctite® 648, commercially available from Henkel Loctite Corp. of AuburnHills, Mich.

With reference to FIGS. 4 and 5, one embodiment of the present inventioncan include an annular member 102 made of steel can be used in lieu ofthe above-mentioned inserts 72. By way of example, the annular member102 can be placed in the foam mold (not shown) of the tube assembly 28such that when the final casting is made, the annular member 102 can bepositioned in an annular depression 104 adjacent to the first end 48.The annular member 102 in the annular depression 104 can be flush to anexterior surface 106 of the tube assembly 28. It will be appreciatedthat the annular member 102 can be located a predetermined distance froma terminus 108 of the first end 48 or flush with the terminus 108, asshown in FIG. 5. It will also be appreciated that the annular member 102can be a complete ring or a partial ring and, to that end, the annulardepression 104 can have a complementary shape (i.e., a partial or a fullring). It will further be appreciated that the distance at which theinserts 72, the pockets 70 and/or the annular member 102 is located fromthe terminus 108 of the first end 48 can be specific to each model ofthe axle assembly 12.

With reference to FIG. 6, the first end of the tube assembly 28 isinserted into the collar 60 on the carrier housing 30. The collar 60 caninclude a stop (not shown) to facilitate placement of the tube assembly28 in the carrier housing 30 at a desired depth. The inserts 72 made ofsteel can be aligned to the plugs 68 and the plugs 68 can be welded tothe inserts 72, for example, using a slug-welding process to therebyfixedly couple the tube assembly 28 to the carrier housing 30. Theslug-welding process briefly includes, for example, heating the plugs 68to a sufficient temperature whereby both the inserts 72 and the plugs 68partially liquefy and then cool to form a single unit. By connecting theplugs 68, which are connected to the carrier housing 30, to the inserts72, which are connected to the tube assembly 28, a steel-to-steel weldis formed. It will be appreciated that when the tube assembly 28 isslug-welded to the carrier assembly 26 both the slug-weld and thepress-fit provide a robust connection to form the axle assembly 12.

Those skilled in the art can now appreciate from the foregoingdescription that the broad teachings of the present invention can beimplemented in a variety of forms. Therefore, while this invention hasbeen described in connection with particular examples thereof, the truescope of the invention should not be so limited since othermodifications will become apparent to the skilled practitioner upon astudy of the drawings, the specification and the following claims.

1. An apparatus comprising: a first member made of a first metal, saidfirst member having a first exterior surface and a first end, wherein apocket is formed in said exterior surface of said first end; an insertmade of a second, different metal connected to said pocket and having asecond exterior surface that is flush with the first exterior surface;and an object formed of the second metal and resistance welded to theinsert; wherein the second metal is steel and wherein the first metal isa metal that cannot be resistance welded directly to steel.
 2. Theapparatus of claim 1 wherein said pocket forms an aperture and saidinsert includes a post, said post disposed in said aperture.
 3. Theapparatus of claim 1 wherein said pocket includes a pair of walls, saidpair of walls each forming a serrated-structure, said insert includes apair of sides, said pair of sides each forming a complementaryserrated-structure to said serrated-structure on said pair of walls,said serrated-structure on said pair of walls connected to saidcomplementary serrated-structure on said pair of sides.
 4. The apparatusof claim 1, wherein said pocket includes a pair of walls and a bottomportion having an angle between each of said pair of said walls and saidbottom portion, and wherein said angle is one of an acute angle, anobtuse angle, and a right angle.
 5. The apparatus of claim 1 furthercomprising an adhesive between said pocket and said insert.
 6. Theapparatus of claim 5 wherein said adhesive is an acrylic adhesive. 7.The apparatus of claim 1 further comprising a fastener connecting saidinsert to said cast iron tube.
 8. The apparatus of claim 7 wherein saidfastener includes a head and said insert includes a top surface that isabout flush with an exterior surface of said tube assembly, and whereinsaid head of said fastener is disposed beneath said top surface of saidinsert.
 9. The apparatus of claim 1 further comprising a top surface ofsaid insert and an exterior surface of said tube assembly, wherein saidtop surface of said insert is about flush with said exterior surface ofsaid tube assembly.